Many failures have been experienced in pipe hanging arrangements used in high temperature chemical furnaces. It has been found that thermal fatigue cracks are often formed in the very thick back wall of a pipe fitting during long term service. One wall of a pipe fitting is inherently thicker or contains more metal than the opposite wall when a boss is formed thereon to which a pipe hanger is secured. Many chemical furnaces operate at temperatures varying from 1,000.degree. to 2,000.degree. F. or more. As the temperature within a furnace fluctuates, a differential in loss of temperature between a thick and a thin wall of a pipe fitting is experienced which in turn causes thermal fatigue and ultimately cracking and failure of the pipe fitting.